IRVING, Texas (AP) — Justin Durant was as sick as anyone to see Sean Lee go down with a torn knee ligament in the first offseason practice for the Dallas Cowboys.

To suggest the injury gives Durant an opportunity to be the starting middle linebacker sort of turns the eight-year veteran's stomach.

"It hurt me seriously to my core," Durant said of the left ACL injury that is likely to keep Lee out in 2014. "I just look at it as my trying to step up and fill some big shoes."

Durant isn't the only option under consideration by the Cowboys, who still haven't specified Lee's injury or said how long they expect him to be sidelined.

Fourth-round pick Anthony Hitchens wasn't far behind Durant for the start of the second week of offseason practice Monday, the same day Hitchens signed his rookie contract. And second-year player DeVonte Holloman worked off to the side, nursing a sore hamstring. If one of those three isn't at the center of the Dallas defense in the season opener against San Francisco in about three months, it will probably be someone off the streets.

The Cowboys aren't in a hurry to decide.

"I don't have timetables," linebackers coach Matt Eberflus said. "I really don't. Like I said, just working with who's on the grass."

Durant and Holloman started the last three games of 2013 after Lee was sidelined by a neck injury.

Durant made the first of those three starts before a hamstring injury sidelined him. Holloman took the last two, and had the first two sacks of his career in the season finale against Philadelphia.

But Holloman hasn't made it the practice field this offseason because of a hamstring injury after the sixth-round pick missed seven games his rookie season with a neck problem. And he was drafted as an outside linebacker.

"The reason he's valuable is he's got position flex," Eberflus said. "Where he fits in the lineup I'm not sure yet. But he'll decide that with his play."

A year after coming to Dallas as a free agent who figured to be a backup, Durant finds himself by far the most experienced option to replace Lee. And that could mean a more vocal role for a guy who blended into the background his first year with the Cowboys.

"Sean of course is a huge leader on our defense," said Durant, who has started 74 of 89 games in his first seven years. "I'm going to be me but I'm also going to step up and I'm going step in and do some things sometimes."

Hitchens was drafted a couple of rounds earlier than most projections, with Dallas thinking about insurance after Lee missed almost half the previous two seasons with injuries. The Cowboys didn't figure on having to cash in on that policy so quickly.

"I just take it as this is my job and this is what they brought me in here for," Hitchens said. "I signed up for this. I usually don't look ahead."

If he's looking ahead, coach Jason Garrett isn't saying. The coach wouldn't rule out a return in 2014 by Lee, who has missed 18 games in four seasons with hamstring, wrist, toe and neck injuries.

"We feel like we have more guys to start with than we had last year at this time," Garrett said. "We want to be sure those guys get an opportunity to show us what they can do. We're also trying to find the best three linebackers."